During the trial, Crown prosecutor Mark O'Donoghue described Shaw as an opportunistic offender who targeted children in public and took opportunities to sexually assault them when their mothers were not present.

The court heard Shaw was in line at the Richmond Pak 'n Save in October 2011 when he indecently touched a 12-year-old.

He was also found guilty of indecently assaulting two sisters, aged 6 and 10, who were playing in an arcade in Richmond Mall that same day, and the indecent assault of two girls in the "family spa" at the ASB Aquatic and Fitness Centre on January 13, 2012.

Defence lawyer Tony Bamford had argued that if his client had touched anyone it was "momentary and innocent", or was in a context that was neither deliberate or indecent, he said.

While no schools were mentioned in the case, Shaw had previously taught at a number of schools in the wider Nelson area.

Shaw was a teacher at Rai Valley School in 2010 but principal Angela Sloane declined to comment.

Nelson College for Girls principal Cathy Ewing confirmed Shaw worked at the college for a short time in 2005. She could not say anything more about the matter because she was not the principal at the time.

The screening protocol was a job reserved for the Teachers Council and its distribution of registration certificates, she said. Teachers Council director Peter Lind said the council had not received any complaints prior to the conviction.

"Since the conviction, he will be referred to us and a disciplinary process will take place. Of course this is a serious matter and we will be dealing with it accordingly."

If complaints had been made to any of the schools the employer was obliged to conduct an investigation, he said.

If an outcome was unsatisfactory, a mandatory report would have to be made to the council.

No reports of this kind had been passed to the council, he said.

In situations like this, the council worked closely with the police and other agencies.